diff --git a/src/linkapp.cpp b/src/linkapp.cpp
index 98eac62..ad0b56e 100644
--- a/src/linkapp.cpp
+++ b/src/linkapp.cpp
@@ -523,7 +523,7 @@ void LinkApp::showManual() {
 
 	// Txt manuals
 	if (manual.substr(manual.size()-8,8)==".man.txt") {
-		string text(readFileAsString(manual.c_str()));
+		string text(readFileAsString(manual));
 		TextManualDialog tmd(gmenu2x, getTitle(), getIconPath(), text);
 		tmd.exec();
 		return;
diff --git a/src/utilities.cpp b/src/utilities.cpp
index 54ecf0e..0bbf636 100644
--- a/src/utilities.cpp
+++ b/src/utilities.cpp
@@ -58,7 +58,7 @@ string rtrim(const string& s) {
 
 // See this article for a performance comparison of different approaches:
 //   http://insanecoding.blogspot.com/2011/11/how-to-read-in-file-in-c.html
-string readFileAsString(const char *filename) {
+string readFileAsString(string const& filename) {
 	ifstream in(filename, ios::in | ios::binary);
 	if (!in) {
 		return "<error opening " + string(filename) + ">";
diff --git a/src/utilities.h b/src/utilities.h
index 2d84e39..cd442ac 100644
--- a/src/utilities.h
+++ b/src/utilities.h
@@ -47,7 +47,7 @@ std::string ltrim(const std::string& s);
 std::string rtrim(const std::string& s);
 
 /** Returns the contents of the given file as a string. */
-std::string readFileAsString(const char *filename);
+std::string readFileAsString(std::string const& filename);
 
 std::string strreplace(std::string orig, const std::string &search, const std::string &replace);
 std::string cmdclean(std::string cmdline);